Anchoring effect of VSL estimates on previous studies
Victor Champonnois  1@  
1 : Aix-Marseille Sciences Economiques  (AMSE)  -  Website
École des Hautes Études en Sciences Sociales : UMR7316, Aix Marseille Université : UMR7316, Ecole Centrale de Marseille : UMR7316, Centre National de la Recherche Scientifique : UMR7316
5-9 Boulevard BourdetCS 5049813205 Marseille Cedex 1 -  France

In this paper, I propose a test for a publication bias suggested by Viscusi and Masterman [2017]. This bias arises from the selection of estimates based on their distance from the usual range in the literature. It implies that, in a given research area, there is a progressive concentration of estimates around this range as the literature grows. I test this hypothesis using OECD meta-data on VSL elicited via stated preferences. Using interquantile regression, I am able to model semi-parametrically the dispersion of estimates as a function of the number of prior studies, controlling for confounding factors. Consistently with the hypothesis, my results show a decrease in the dispersion for the lower part of the conditional distribution. I find no significant pattern for the upper part of the conditional distribution. This result has two implications. First, there is a systematic underestimation of the variance of mean estimates in meta-analyses of VSL. Second, there is an upward bias in the mean estimate of VSL meta-analyses due to the asymmetry of the selection pattern. Both implications might also affect meta-analyses in other research areas.

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